Listen To The Lion

A Neptune-sized planet orbiting a brown dwarf star in the constellation Leo is discombobulating Science Men because it refuses to have methane.

Science Men had previously decreed that all planets of this size and temperature must have methane. They apparently grounded this belief on the observation that the planets in our solar system of that size and temperature possess methane.

“The ball is in the theorists’ court now,” taunted Kevin Stevenson, Ph.D student at the University of Central Florida, and lead author of the study that determined that the planet, monikered GJ 436b, had successfully resisted the Science Men’s command that all such planets exhibit methane. “They will have to improve their models, taking into account the disequilibrium processes that could account for what is happening. The current models are a very good first step in determining the atmospheres of these planets, but now we need to go a step further.”

“What this does tell us is that there is room for improvement in our models,” opined Joseph Harrington, associate professor at the University of Central Florida. “The lesson here is that planets really do have individual personalities.”

Duh.

Three years ago this same planet caused serious contortions among Science Men when they determined that it seems to be composed mostly of water, although its surface temperature is over 600 degrees. Therefore, they divined, it must be something they would call a “hot ice planet,” shamelessly harboring “exotic forms of water.”

Why would the Science Men think this? Because fumbling around for “models” here in our own solar system, they stumbled across Uranus and Neptune, and so figured GJ 436b must be one of Them.

Why would astronomers guess that the planet is made of “hot ice?” First, in our solar system, the planets Uranus and Neptune, the planets closest in size and average density to GJ 436b, are thought to be made of ices (including water ice) covered by an extraordinarily thick atmosphere of methane. So, it is not unreasonable to guess that all planets the size and density of Neptune and Uranus look like Neptune and Uranus. But, again, this is just an educated guess . . . .

[I]f GJ 436b has a very thick atmosphere, like Uranus and Neptune, the pressure inside the planet can be high enough to make water turn into ice, even though it would be very hot! This ice is not quite like ice on Earth—the structure of ice crystals on Earth is not the same structure of ice crystals at high pressure. And, if this hypothesis is right, most likely the atmosphere of the planet would go through a gradual transition from air to liquid to solid. This is quite unlike the Earth, where there is an abrupt transition from the atmosphere to the sea and again from the sea to the sea floor. On GJ 436b, there is probably no real “surface” to the planet.

Of course now we know the above theory is shot to hell because GJ 436b refuses to have any methane. Science Men just naturally figured it would, because:

All of the giant planets in our solar system have methane in their atmospheres. On Earth, methane is manufactured primarily by microbes living in cows and soaking in waterlogged rice fields.

Neptune is blue because of this chemical, which absorbs red light. Methane is a common ingredient of relatively cool bodies, including brown dwarfs, which are cool, dim substars.

In fact, any planet with the common atmospheric mix of hydrogen, carbon and oxygen, and a temperature of up to 1,340 degrees Fahrenheit (727 degrees Celsius) is expected to have a large amount of methane and a small amount of carbon monoxide. That’s because under these temperatures, any carbon present should be chemically favored to be in the form of methane.

GJ 436b is busy racing around its brown dwarf on a 2.64-day orbit; Science Men can see it when it crosses in front of its star. That the planet is both large and orbits around a brown dwarf makes its refusal to have methane particularly Wrong.

“A lot of the larger planets and brown dwarfs are thought to have similar atmospheric behavior,” said Harrington. “Brown dwarfs pretty much all follow a fairly straight-forward atmospheric chemistry that is not difficult to predict. Many theorists have applied these models to hot exoplanets, but in this case it doesn’t work.”

As we now know that it is “reasonable to assume there are more [exosolar planets] than stars in our galaxy,” Science Men need to abandon the silly notion that they can construct “models” accounting for all planets in the universe based solely upon conditions here on Earth and our eight neighbors orbiting Sol.

That would be like me observing myself and my eight nearest neighbors, and concluding thereby that the entire planet is heavily forested, served by dirt roads, overrun by skunks and scrub jays, and inhabited by people who speak only English, station giant metallic ants outside their homes, worship alternatively cats, old broken-down cars, and unregistered firearms, and while away their days cultivating and testing “medical” marijuana.

Good luck especially trying to convince any and all planets located in the constellation Leo to behave. Science Men wanting to get a handle on how to tame those beasts best study the Tarot, not astronomy.